[LeetCode] 513. Find Bottom Left Tree Value_ Medium tag: BFS...
这个题的思路其实跟[LeetCode] 199. Binary Tree Right Side View_ Medium tag: BFS, Amazon里面我提到的left side view一样的思路, 只是返回的时候返回最后一个元素即可. 1. Constraints 1) root cannot be None, 所以edge case就是 1 2, Ideas BFS: T: O(n), S: O(n) n is the number of the...